Signal reproducing apparatus and signal reproducing method

ABSTRACT

A signal reproduction device and signal reproduction method capable of automatically discriminating the format of input data and reproducing the data is provided. The signal reproduction device comprises an IEEE 1394 link chip  12 , which receives transmission signals obtained by converting data in a plurality of prescribed signal formats into a prescribed packet format and transmitting, and reproduces signals in a prescribed signal format from the received transmission signals in packet form, as well as an IEEE 1394 microcontroller  13 , which extracts a prescribed packet of received transmission signals, detects data in the extracted packet indicating modification from the signal format currently being received to another prescribed signal format, and based on the detected signal format modification data, outputs parameters necessary for reproduction of signals in another prescribed signal format from received signals in packet form; and the signal reproduction device automatically discriminates the data format of input data and reproduces the data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. § 371 ofinternational application PCT/JP02/06114, filed Jun. 19, 2002, whichclaims the benefit of Japanese Application Nos. JP2001-185252, filedJun. 19, 2001, and JP2002-171797, filed Jun. 12, 2002, the disclosuresof all of which are incorporated by reference herein in their entirety.

TECHNICAL FIELD

This invention relates to a signal reproduction device and signalreproduction method for signal format recognition in, for example, amulti disc player and audio-video (AV) amplifier.

BACKGROUND ART

Conventionally, in interfaces conforming to the IEEE 1394 standard, forexample between signal recording and reproduction devices, music data istransmitted and received, and music data which had been recorded in onesignal recording and reproduction device is reproduced in another signalrecording and reproduction device.

DISCLOSURE OF THE INVENTION

However, there is the problem that, because there is no means forrecognizing the data format for AM824E standard data used by theabove-described conventional signal recording and reproduction device tosend and receive music data through an interface conforming to the IEEE1394 standard, if the contents of the data are not examined, the dataformat cannot be determined.

However, actual examination of data contents requires time, so thatthere is the problem that audio interruptions and absence of trackbeginnings occur.

As a method other than that described above, it is possible forequipment which sends and receives music data to perform negotiation inorder to conduct communications, and to set a communication protocol fortransmission and reception; however, the method for setting acommunication protocol for this purpose is not stipulated in thestandards, and so when setting the communication protocol, there is theproblem that the format must be recognized based on the data contents.

This invention was devised in light of the above problems, and has as anobject the provision of a signal reproduction device and signalreproduction method enabling the automatic discrimination of the dataformat of, and reproduction of, input data.

A signal reproduction device of this invention comprises reception meansto receive transmitted transmission signals resulting from theconversion of data in a plurality of prescribed signal formats into aprescribed packet type; reproduction means to reproduce signals in aprescribed signal format from transmission signals received by thereception means and converted into packets; packet extraction means toextract a prescribed packet of transmission signals received by thereception means; modification data detection means to detect, in anextracted packet, data indicating that modification has been performedfrom the currently received prescribed signal format to anotherprescribed signal format; and, control means to send, to thereproduction means, parameters necessary for reproduction by thereproduction means, from signals received and converted into packets tosignals in another prescribed signal format, based on detected signalformat modification data.

Further, a signal reproduction method of this invention comprises areception step, in which transmission signals, obtained by convertingdata in a plurality of prescribed signal formats into a prescribedpacket format and transmitting, are received; a reproduction step, inwhich signals in a prescribed signal format are reproduced fromtransmission signals converted into packet form, received in thereception step; a packet extraction step, in which a prescribed packetof transmission signals received in the reception step is extracted; amodification data detection step, in which data is detected, in anextracted packet, indicating that modification has been performed fromthe currently received prescribed signal format to another prescribedsignal format; and, a control step, in which, based on the detectedsignal format modification data, parameters necessary for reproductionof signals in another prescribed signal format from received signalsconverted into packets in the reproduction step are sent to thereproduction step.

Hence the action according to this invention is as follows.

The reception means acts to receive transmission signals, which are datain a plurality of prescribed signal formats converted into a prescribedpacket format and transmitted. The reproduction means acts to reproducesignals in a prescribed signal format from transmission signals,converted into packets, which have been received by the reception means.The packet extraction means acts to extract a prescribed packet of thetransmission signals received by the reception means. The modificationdata detection means acts to detect data, from an extracted packet,indicating that modification has been performed from a prescribed signalformat of the currently received signals to another prescribed signalformat. The control means acts, based on the detected signal formatmodification data, to send to the reproduction means parametersnecessary to reproduce signals in other prescribed signal formats fromsignals converted into packets and received by the reception means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of a communicationsystem to which this aspect is applied;

FIG. 2 is a drawing showing detection of a data stream change by aregister;

FIG. 3 is a drawing showing the IEEE 1394 packet structure;

FIG. 4 is a drawing showing the data of an IEEE 1394 packet;

FIG. 5 is a drawing showing an IEC 60958 (CD, MD) packet;

FIG. 6 shows a DVD packet;

FIG. 7 shows the first packet among SACD packets;

FIG. 8 shows the second and subsequent packets among SACD packets;

FIG. 9 shows an IEC 60958 (CD, MD) Ancillary No-data packet;

FIG. 10 shows a DVD Ancillary No-data packet;

FIG. 11 shows an SACD Ancillary No-data packet;

FIG. 12 shows a register for stream change detection of AM824 packetdata;

FIG. 13 shows a stream change;

FIG. 14 is a flowchart showing the operation to judge packet dataformats using a register;

FIG. 15 is a drawing showing an example of a stream change from IEC60958 to SACD;

FIG. 16 is a drawing showing an example of a stream change from SACD toIEC 60958;

FIG. 17 is a drawing showing an example of a stream change from SACD toDVD;

FIG. 18 is a drawing showing an example of a stream change from SACD5-channel format to SACD 6-channel format;

FIG. 19 is a drawing showing a reception state when a receiver receivesstream data; and,

FIG. 20 is a drawing showing a reception state when a receiver receivesstream data.

BEST MODE FOR CARRYING OUT THE INVENTION

Below, an aspect of this invention is explained.

A signal reproduction device of this aspect examines received datapackets and automatically recognizes data formats, and can be appliedto, for example, data in an IEC 60958-conformant format among formatsconforming to Audio and Music Data Transmission Protocol 1.0 and AMDTR2.0, as well as data in DSD (Digital Stream Direct) format, and data inDVD (Digital Versatile Disc) Audio format.

FIG. 1 is a block diagram showing the configuration of a communicationsystem to which this aspect is applied.

In FIG. 1, a multiformat-compatible transmitter 1 andmultiformat-compatible receiver 11 are connected via, for example, anetwork 9 conforming to the IEEE 1394 standard, and, for example, datain an IEC 60958-conformant format, SACD (Super Audio Compact Disc)format data as DSD format data, CD (Compact Disc) format data, DVD Audioformat data, or similar data 10 is transmitted from themultiformat-compatible transmitter 1 to the multiformat-compatiblereceiver 11.

The multiformat-compatible transmitter 1 is configured to have a disc 2as recording media on which is recorded the data 10; a CD/SACD/DVD DSP(Digital Signal Processor) 3 which performs reproduction signalprocessing of data in various formats, recorded on the disc 2; an IEEE1394 link chip 4, which makes settings for transmission of the data 10over a network conforming to the IEEE 1394 standard; an IEEE 1394microcontroller 5, which controls the IEEE 1394 link chip 4; a systemmicrocontroller 6, which controls the multiformat-compatible transmitter1; an operation portion 7 capable of various input in order to operatethe multiformat-compatible transmitter 1; and a display portion 8 whichdisplays the status of operation of the multiformat-compatibletransmitter 1.

The multiformat-compatible receiver 11 is configured to have an IEEE1394 link chip 12, which makes settings for reception of the data 10over a network conforming to the IEEE 1394 standard; an IEEE 1394microcontroller 13, which controls the IEEE 1394 link chip 12; a systemmicrocontroller 14, which controls the multiformat-compatible receiver11; an operation portion 15 capable of various input in order to operatethe multiformat-compatible receiver 11; a display portion 16 whichdisplays the status of operation of the multiformat-compatible receiver11; a D/A converter 17 which converts 6-channel digital data received bythe IEEE 1394 link chip 12 into analog signals; and a speaker 18 whichreproduces and acoustically outputs the converted analog signals.

The IEEE 1394 microcontroller 13 is a host controller, and has afunction for performing reception format settings 20 of the IEEE 1394link chip 12 by performing CFR (configuration register) reading from theIEEE 1394 link chip 12.

FIG. 2 is a drawing showing detection of a data stream change by aregister within the above-described IEEE 1394 link chip 12.

In FIG. 2, the data 10 on the IEEE 1394-standard network 9 shown in FIG.1 is configured of IEEE 1394 packets 21. An IEEE 1394 packet 21 isconfigured to have an 1394 header 22, a CRC (cyclic redundancy check)and CIP (common isochronous protocol) header 23, and AM824 data 24. TheAM824 data 24 is data in an above-described CD/SACD/DVD audio format.

The data 10 on the IEEE 1394-standard network 9 is received andprocessed in the IEEE 1394 link chip 12, and in the above-described CFRregister 26, is allocated to RxLABEL 26-1, which makes receptionsettings; INT 26-2, which performs interrupt processing for the systemmicrocontroller 14 depending on the combination of received signals; andSubLABEL 26-3.

The AM824 data 24 of the above-described IEEE 1394 packet 21 is data24-1 having data regions for various formats; this data 24-1 isconfigured to have, for example, data 25 having beginning-portionancillary data 25-1 and actual data 25-2. Here, ancillary data 25-1 isadditional data for the actual data 25-2, and indicates data such as thenumber of channels and the speaker placement.

In this IEEE 1394 link chip 12, AM824 data 24 in an IEEE 1394 packet 21is such that the data format cannot be determined if the data contentsare not observed. Hence in the IEEE 1394 link chip 12, reception signaldata is allocated to the register 26, and by having the register 26 setflags according to the data format of the reception signals, the systemmicrocontroller 14 can detect flags and automatically discriminate theformat of the data 24.

For example, 8000 items of the AM824 data 24 of an IEEE 1394 packet 21are input in one second, and by detecting values indicated by INT26-2performing the allocation processing of the system microcontroller 14 bycombining signals received in the register 26, as well as detectingancillary no-data for detection of stream changes, the systemmicrocontroller 14 detects stream changes occurring over an interval of10 msec or longer. Here the ancillary no-data 28 indicates that the dataof this one sample is invalid, and that the data is not audio processedand output. In this aspect, when such data is detected, stream changedetection can be performed.

When the system microcontroller 14 detects a stream change, onrecognizing that there has been a change in the signal data format, thedata is supplied to a later-stage audio processing circuit.

FIG. 3 is a drawing showing the IEEE 1394 packet structure.

FIG. 3 shows the data structure when transmitting the above-describedAM824 data 24 shown in FIG. 2 over an IEEE 1394-standard network 9. Theheader regions 24-1 to 24-4 are similar to 22 and 23 in FIG. 2.

The data 24-5 are configured to have an unspecified region 31,comprising a detection data region 31-1 in the leading portion, aspecified region 32, and a specified region 33. The specified region 32is configured to have common/application specifier ancillary data,having a common data region in a variety of formats. The specifiedregion 33 is configured to have common/AS ancillary data, having acommon data region in a variety of formats. While standards permit theintermixing and sending of data in various formats in the specifiedregions 32 and 33, for practical reasons data is sent separately foreach of the different formats. Also, a data CRC 34 is provided at theend.

FIG. 4 is a drawing showing the data of an IEEE 1394 packet.

FIG. 4 shows the structure of the data 24-1 shown in FIG. 3 above.

In FIG. 4, 31 shows the structure of data for CDs, MDs (minidiscs) andsimilar in an IEC 60958-conformant format. 44 shows the structure ofdata of CDs, MDs (minidiscs) and similar for ancillary no-data for anIEC 60958-conformat format. This data 41 in an IEC 60958-conformantformat (CD, MD) and data 44 in an ancillary no-data for an IEC60958-conformant format (CD, MD) are discriminated according to whetherthe upper 4 bits of the register value indicated by 47 is “0000”(binary) while the lower 4 bits is, as an arbitrary value from “0000” to“1111”, “xxxx” (binary), and whether the upper 8 bits of the registervalue indicated by 47-1 is “CF” (hexadecimal) while the lower 8 bits is“00” (hexadecimal).

Further, 42 shows the structure of multi-bit linear audio format DVDaudio and other data; 45 shows the structure of DVD audio and other datain the ancillary no-data for multi-bit linear audio format. Themulti-bit linear audio format (DVD audio) data 42 is discriminated byeither “D0” (hexadecimal) in the upper 8 bits of the value of theregister indicated by 48 and “01” (second quadlet “02”) (hexadecimal) inthe lower 8 bits, or by “CF” (hexadecimal) in the upper 8 bits of thevalue of the register indicated by 48-1, and “D0” (hexadecimal) in thelower 8 bits.

Further, 43 indicates the structure of SACD and other data in a one-bitaudio data format; 46 indicates the structure of SACD and other data inan ancillary no-data for one-bit audio data format. The one-bit audiodata format (SACD) data 43 and the ancillary no-data for one-bit audiodata format (SACD) data 46 are discriminated by either “D1” (secondquadlet “50”) (hexadecimal) in the upper 8 bits of the value of theregister indicated by 49 and “00” (hexadecimal) in the lower 8 bits, orby “CF” (hexadecimal) in the upper 8 bits of the value of the registerindicated by 49-1, and “D1” (second quadlet “50”) (hexadecimal) in thelower 8 bits.

FIG. 5 is a drawing showing an IEC 60958 (CD, MD) packet.

In FIG. 5, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. The first quadlet 501 comprises thebinary “0000xxxx” indicated in 505 and a data L (left) channel; thefollowing second quadlet comprises the binary “0000xxxx” indicated in505 and a data R (right) channel; and these two quadlets constitute onesample 502. Samples similar to this one sample 502 are provided in the 8samples up to sample 502-8 in 503, for a total of 16 quadlets 504.

FIG. 6 shows a DVD packet.

In FIG. 6, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. As indicated by 601, one quadletconsists of the hexadecimal “D001” indicated by 605 and ancillary data;the following second quadlet consists of the hexadecimal “D002”indicated by 605 and ancillary data. As indicated by 602, the thirdquadlet consists of the hexadecimal “48” indicated by 605 and datachannel 1, and the following fourth quadlet consists of the hexadecimal“48” indicated by 605 and data channel 2, and similarly until the eighthquadlet, which consists of the hexadecimal “48” indicated by 605 anddata channel 6. The eight quadlets 601 and 602 constitute one sample603, and similar samples 602-2 through 602-16 make up 16 samplesprovided in 604.

FIG. 7 shows the first packet among SACD packets. Only the first packetof SACD audio data has the following structure.

In FIG. 7, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. As indicated by 701, the first quadletconsists of a hexadecimal “D100” and ancillary data; as indicated by702, the following second quadlet consists of a hexadecimal “50” and adata 1 channel; the third quadlet consists of a hexadecimal “51” and adata 2 channel; and so on, until the seven quadlet consists of ahexadecimal “51” and a data 6 channel, and as indicated by 703, theeighth quadlet consists of a hexadecimal “CFCF” and no-data. One sample704 consists of the eight quadlets 701, 702, 703; similar samples 704-2,. . . , 704-16 are provided in the 16 samples 705.

FIG. 8 shows the second and subsequent packets among SACD packets. Thesecond and subsequent packets of the SACD audio data has the followingstructure.

In FIG. 8, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. As indicated by 801, the first quadletconsists of a hexadecimal “CFD1” and no-data; as indicated by 802, thefollowing second quadlet consists of a hexadecimal “50” and a data 1channel; the third quadlet consists of a hexadecimal “51” and a data 2channel; and so on, until the seven quadlet consists of a hexadecimal“51” and a data 6 channel, and as indicated by 803, the eighth quadletconsists of a hexadecimal “CFCF” and no-data. One sample 804 consists ofthe eight quadlets 801, 802, 803; similar samples 804-2, . . . , 804-16are provided in the 16 samples 805.

FIG. 9 shows an IEC 60958 (CD, MD) ancillary no-data packet. It isassumed that, when sending CD audio data, there is no need to sendancillary no-data indicating a stream change; however, such data may besent. In IEC 60958 audio data, ancillary no-data must be output betweendata portions. Hence when IEC 60958 (CD, MD) audio data is transmitted,because there are cases in which ancillary no-data is sent, this must bedetected. An IEC 60958 (CD, MD) ancillary no-data packet is a packetwhich is sent between transmission of data portions of IEC 60958 (CD,MD) data from the transmission device to a device on the network capableof receiving data.

In FIG. 9, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. The first quadlet 901 consists of ahexadecimal “CF00”, indicated by 901, with no data; the following secondquadlet consists of a hexadecimal “CF00” indicated by 905 and no data;this second quadlet constitutes one sample 902. 8 samples 903 up to902-8 similar to this one sample 902 are provided, for a total of 16quadlets 904.

FIG. 10 shows a DVD ancillary no-data packet. When sending DVD audiodata, it is assumed that ancillary no-data indicating a stream changemust be output between data portions. The DVD audio ancillary no-datapackets described below are packets transmitted between transmission ofDVD audio data from a transmission device to a device on the networkcapable of receiving data. In the case of DVD audio data, by detectingancillary no-data together with actual data, stream changes aredetected.

In FIG. 10, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. As indicated by 1001, first quadletconsists of a hexadecimal “CFD0”, indicated by 1005 and ancillary data;the following second quadlet consists of a hexadecimal “CFD0” indicatedby 1005 and ancillary data. As indicated by 1002, the third quadletconsists of a hexadecimal “CF48” indicated by 1005 and no data, thefollowing fourth quadlet consists of a hexadecimal “CF48” indicated by1005 and no data, and quadlets continue similarly to the eighth quadlet,consisting of a hexadecimal “CF48” indicated by 1005 and no data. Onesample 1003 consists of the 8 quadlets 1001 and 1002; similar samplescontinue for 16 samples 1004, from 1003-2 to 1003-16.

Here, by detecting, in the second and subsequent packets, that the firstquadlet consists of “CFD0” and ancillary data, the following secondquadlet consists of “CFD0” and ancillary data, and that the thirdquadlet consists of “CF48” and no data, stream changes can be detected.

FIG. 11 shows an SACD ancillary no-data packet. It is assumed that, whensending SACD audio data, ancillary no-data indicating a stream changemust be output between data portions. The SACD audio ancillary no-datapackets described below are packets transmitted between transmission ofSACD audio data from a transmission device to a device on the networkcapable of receiving data.

In FIG. 11, the 1394 header 24-1, CRC 24-2, and CIP 1, 2 (24-3, 4) aresimilar to those shown in FIG. 3. As indicated by 1101, first quadletconsists of a hexadecimal “CFD1” and no data; the following secondquadlet consists of a hexadecimal “CF50” and no data, the third quadletconsists of a hexadecimal “CF51” and no data, and so on until theseventh quadlet consists of a hexadecimal “CF51” and no data, and theeighth quadlet consists of a hexadecimal “CFCF” and no data. One sample1101 consists of the eight quadlets; similar samples from 1101-2 to1101-16 are provided in the 16 samples 1102.

FIG. 12 shows a register for stream change detection of AM824 packetdata. This register is provided such that input packets can be detectedfrom the microcontroller. Input packets and this register are in aone-to-one correspondence.

In each of the following drawings, changing the value set for a flag ineach register from “0” to “1” is simply called turning on the flag foreach register.

In FIG. 12, in the method of stream change detection of this aspect, CFdetection means detects whether the leading byte of the first quadlet ofAM824 packet data is CF58-1 and moreover the leading byte of the secondquadlet is CF58-2. The CF detection means comprises, for example, alogic circuit or a software module. At this time, the CF detection meansturns on RxLABEL CF57, and when the system microcontroller 14 detectsthe on state of RxLABEL CF57, the occurrence of a stream change in theAM824 packet data can be detected. Detection of the fact that theleading byte of the first quadlet is CF58-1 and moreover the leadingbyte of the second quadlet is CF58-2 can be performed by, for example,taking the output of an AND circuit the input of which is the two dataitems CF58-1 and CF58-2 as input to turn on RxLABEL CF57, and detectingand preferentially processing the on state of RxLABEL CF57 throughinterrupt processing of the system microcontroller 14.

Next, the CF50 detection means detects whether the leading two bytes ofthe first quadlet of the AM824 packet data are CFD1, and moreover theleading two bytes of the second quadlet are CF50. For example, the CF50detection means comprises a logic circuit or software module. At thistime, the CF50 detection means turns on the CF50 flag 51, and bydetecting the on state of the CF50 flag 51, the system microcontroller14 can detect the occurrence of a stream change of AM824 packet data toSACD data 52. Here the CF50 detection means detects, as a simpledetection method, only whether the leading two bytes of the secondquadlet are CF50, and turns on the CF50 flag 51.

Next, the CFD0 detection means detects whether the leading two bytes ofthe first quadlet of the AM824 packet data are CFD0, and moreover theleading two bytes of the second quadlet are CFD0. The CFD0 detectionmeans comprises, for example, a logic circuit or a software module. Atthis time, the CFD0 detection means turns on the CFD0 flag 53, and bydetecting the on state of the CFD0 flag 53, the system microcontroller14 can detect the occurrence of stream changes in the AM824 packet datato DVD-audio data 54. Here the CFD0 detection means may detect, as asimple detection method, only whether the leading two bytes of thesecond quadlet are CFD0, and turn on the CFD0 flag 53.

Next, the Rx label detection means detects whether the upper four bitsof the first quadlet of the AM824 packet data are 0000. The Rx labeldetection means comprises, for example, a logic circuit or softwaremodule. At this time, the Rx label detection means turns on RxLABEL 055,and by detecting the on state of the RxLABEL 055, the systemmicrocontroller 14 can detect a stream change in AM824 packet data toCD/MD data (IEC 60958) 56. Detection that the upper four bits of thefirst quadlet are 0000 can be performed by, for example, taking theoutput of an AND circuit employing four data bits 0000 as negative-logicinput as input to turn on RxLABEL 055, and performing detection andpreferential processing through interrupt processing of the systemmicrocontroller 14.

Of the AM824 packet data, the audio label 59-1 and audio sub-label 59-2of the first quadlet and second quadlet are stored in the IBO register59. At this time, the system microcontroller 14 detects the audio label59-1 and audio sub-label 59-2 of the IBO register 59, and by this meanscan confirm the data format of the AM824 packet data.

FIG. 13 shows a stream change.

In FIG. 13, the stream change function for the AM824E stream 61 isexplained. The ancillary no-data described below is data sent betweentransmission data portions from a transmission device to a device on thenetwork capable of receiving data.

In FIG. 13, during transmission of for example IEC 60958 data 64 in anAM824E stream 61, by transmitting the IEC 60958 ancillary no-data 65 inthe interval of 10 msec or longer between time T1 and time T2, and byhaving the transmission device transmit as special data SACD ancillaryno-data 66 in the interval of 10 msec or longer between time T2 and timeT3, a stream change is performed in the AM824E stream 61 from IEC 60958data 64 to SACD data 67. In this case data prior to time T2 is definedas the IEC 60958 context 62, and data after time T2 is defined as theSACD context 63.

By this means, ancillary no-data in formats before and after conversionby the device on the data reception side can be discriminated andreception settings made, so that format conversion discrimination ispossible. Also, stream changes can be detected using data with fewcombinations, and, at this time, by turning on various flags in theabove-described registers to enable easy detection by the systemmicrocontroller 14, the load on the host controller can be alleviated.

Next, judgment of the format of packet data being received throughoperation of the microcontroller using the registers is explained. Thefollowing processing and judgment are performed by, for example, amicrocontroller, but the present invention is not thus limited, andother judgment means may be used, so long as judgments of the formats ofpacket data allocated to registers can be made from the states of theregisters.

FIG. 14 is a flowchart showing the operation to judge packet dataformats using a register.

In FIG. 14, in step S1 a judgment as to whether RxLABEL CF=1 orRxLABEL0=0 is made.

In step S1, if RxLABEL CF=1 or RxLABEL0=0, processing proceeds to stepS2, and in step S2, a judgment is made as to whether RxLABEL CF50=1 andmoreover RxLABEL CFD0=0 and moreover RxLABEL0=0.

In step S2, when RxLABEL CF50=1 and moreover RxLABEL CFD0=0 and moreoverRxLABEL0=0, processing proceeds to step S3, and in step S3, a judgmentis made as to whether the packet data is in a 1-bit audio (SACD) format.

When in step S1 it is not the case that RxLABEL CF=1 or that RxLABEL0=0,processing proceeds to step S13, and in step S13, a judgment is made asto whether the packet data is in an IEC 60958 format.

In step S2, when it is not the case that RxLABEL CF50=1 and moreoverRxLABEL CFD0=0 and moreover RxLABEL0=0, processing proceeds to step S4,and in step S4, a judgment is made as to whether RxLABEL CF50=0 andmoreover RxLABEL CFD0=1 and moreover RxLABEL0=0.

In step S4, when RxLABEL CF50=0 and moreover RxLABEL CDD0=1 and moreoverRxLABEL0=0, processing proceeds to step S5, and in step S5 the packetdata is judged to be in a multi-bit audio (DVD audio) format.

In step S4, when it is not the case that RxLABEL CF50=0 and moreoverRxLABEL CFD0=1 and moreover RxLABEL0=0, processing proceeds to step S6,and in step S6 a judgment is made as to whether RxLABEL CF50=0 andmoreover RxLABEL CFD0=0 and moreover RxLABEL0=0.

In step S6, when RxLABEL CF50=0 and moreover RxLABEL CFD0=0 and moreoverRxLABEL0=0, processing proceeds to step S7, and in step S7 a judgment ismade as to whether the packet being received is IEC 60958-conformant oris an empty packet.

In step S7, when the packet being received is IEC 60958-conformant or isan empty packet, processing proceeds to step S8, and in step S8, thepacket data is judged to be in the IEC 60958 format.

In step S7, if it is not the case that the packet being received is IEC60958-conformant or is an empty packet, processing proceeds to step S9,and in step S9, a judgment is made as to whether the packet beingreceived is in a 1-bit audio (SACD) format.

In step S9, when the packet being received is in a 1-bit audio (SACD)format, processing proceeds to step S10, and in step S10, the packetdata is judged to be in a 1-bit audio (SACD) format.

In step S9, when the packet being received is not in a 1-bit audio(SACD) format, processing proceeds to step S11, and in step S11, ajudgment is made as to whether the packet being received is in amulti-bit audio (DVD audio) format.

In step S11, when the packet being received is in a multi-bit audio (DVDaudio) format, processing proceeds to step S12, and in step S12, thepacket data is judged to be in a multi-bit audio (DVD audio) format.

After the judgment of a 1-bit audio (SACD) format in step S3, thejudgement of a multi-bit audio (DVD audio) format in step S5, thejudgment of an IEC 60958 format in step S8, the judgment of a 1-bitaudio (SACD) format in step S10, the judgment of a multi-bit audio (DVDaudio) format in step S12, and the judgment of an IEC 60958 format instep S13, processing proceeds to step S14, and in step S14, each of theflags is cleared.

Next, examples of stream changes among various formats of packet databeing received are explained.

In the following drawings, detection, judgment, and other operations maybe performed by, for example, a microcontroller; however, this inventionis not thereby limited, and other judgment means may be used, so long asjudgments of the formats of packet data allocated to registers can bemade from the states of the registers.

FIG. 15 is a drawing showing an example of a stream change in whichpacket data changes from IEC 60958 format to SACD format.

In FIG. 15, prior to the time T1, RxLABEL CF50=0, RxLABEL CFD0=0,RxLABEL0=1, and RxLABEL CF=0, so that the format of the received packetdata is the IEC 60958 (81) state. This state is the state in whichpacket data is judged in step S13 to be in IEC 60958 format as a resultof a “NO” branch in step S1 of the flowchart of the above-described FIG.7.

At time T1, as indicated by 85, the value of RxLABEL0 changes from 1(on) to 0 (off), so that a stream change ending IEC60958 Conformant datais detected.

At this time, as shown in FIG. 12, the RxLABEL detection means detectsthat the leading byte of the first quadlet among the packet data is0000, and the RxLABEL detection means turns on RxLABEL055 and bydetecting the on state of RxLABEL055, the system microcontroller 14 as ajudgment means detects a stream change where the CD/MD data (IEC60958)56 end.

In the interval from time T1 to time T2, RxLABEL CF50=0, RxLABEL CFD0=0,RxLABEL0=0, and RxLABEL CF=indefinite, so that the received packet datais in the state of an empty packet 82. This state is the state in whichempty packet data is judged in step S7 as a result of a “YES” branch instep S6 of the flowchart of the above-described FIG. 7.

In the interval from time T2 to time T3, RxLABEL CF50=1, RxLABEL CFD0=0,RxLABEL0=0, and RxLABEL CF=1, so that the received packet data is in thestate of SACD ancillary no-data 83.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet among the packet data is CF58-1and that the leading byte of the second quadlet is CF58-2, and the CFdetection means turns on RxLABEL CF57, so that the systemmicrocontroller 14, by detecting the on state of RxLABEL CF57, detectsthe occurrence of a stream change in the packet data.

Next, the CF50 detection means detects that the leading 2 bytes of thefirst quadlet among the packet data are CFD1 and the leading 2 bytes ofthe second quadlet are CF50, and the CF50 detection means turns on theCF50 flag; the system microcontroller 14, by detecting the on state ofthe CF50 flag 51, detects the occurrence of a stream change in the AM82packet data to SACD data 52.

As indicated by 86, the RxLABEL on state is one CF50 only, so that thepacket data is judged to be the SACD format of the on state of thisRxLABEL CF50. At this time, the received packet is confirmed, the datalength is confirmed, and the IEEE 1394 microcontroller 13 shown in FIG.1 sets the IEEE 1394 link chip 12 to the SACD 84 format reception state.

At time T3, RxLABEL CF50=0, RxLABEL CFD0=0, RxLABEL0=0, and RxLABELCF=0, so that the received packet data is in the state of the SACDformat. This state is the state in which the packet data is judged to bein 1-bit audio (SACD) format in step S3, as a result of a “YES” branchin step S2 of the flowchart in the above-described FIG. 7.

As indicated by 87, the value of RxLABEL CF has changed from 1 (on) to 0(off), and so it is judged that a stream change from IEC60958-conformant to SACD has ended.

FIG. 16 is a drawing showing an example of a stream change of packetdata from SACD format to IEC 60958 format.

In FIG. 16, prior to the time T1, RxLABEL CF50=0, RxLABEL CFD=0,RxLABEL0=0, and RxLABEL CF=0, so that the format of the received packetdata is the state of SACD 91. This state is the state in which packetdata is judged in step S10 to be in the 1-bit audio (SACD) format as aresult of a “YES” branch in step S9 of the flowchart of theabove-described FIG. 7.

At time T1, as indicated by 95, the value of RxLABEL CF50 changes from 0(off) to 1 (on), so that a stream change ending SACD 91 data isdetected.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet among the packet data is CF58-1and that the leading byte of the second quadlet is CF58-2, and the CFdetection means turns on RxLABEL CF57; the system microcontroller 14, bydetecting the on state of RxLABEL CF57, detects that a stream change hasoccurred in the packet data.

Next, the CF50 detection means detects that the leading two bytes of thefirst quadlet of the packet data are CFD1 and that the leading two bytesof the second quadlet are CF50, and the CF50 detection means turns onthe CF50 flag 51; the system microcontroller 14, by detecting the onstate of the CF50 flag 51, detects the occurrence of a stream change inthe AM824 packet data to SACD data 52.

In the interval from time T11 to time T12, RxLABEL CF50=1, RxLABELCFD0=0, RxLABEL0=0, and RxLABEL CF=1, so that the received packet datais in the state of SACD ancillary no-data 92.

In the interval from time T12 to time T13, RxLABEL CF50=0, RxLABELCFD0=0, RxLABEL0=0, and RxLABEL CF=indefinite, so that the receivedpacket data is in the state of the empty packet 93. This state is thestate in which a packet is judged in step S7 to be an empty packet as aresult of a “YES” branch in step S6 of the flowchart of theabove-described FIG. 7.

As indicated by 96, all RxLABEL flags are in the off state, so that databeing received is judged to be IEC 60958-conformant data. Further,because RxLABEL0=0, a stream change is judged to occur. In order toreliably identify the data, the audio label and sub-label of the databeing received are investigated, and the IEEE 1394 microcontroller 13shown in FIG. 1 sets the IEEE 1394 link chip 12 into the IEC60958-conformant 94 reception state.

At this time, the Rx label detection means detects that the upper fourbits of the first quadlet of the packet data are 0000, and the Rx labeldetection means turns on RxLABEL 055; as the judgment means, the systemmicrocontroller 14 detects the on state of RxLABEL 055, and in this waydetects a stream change to CD/MD data (IEC 60958) 56.

Further, the audio label 59-1 and audio sub-label 59-2 of the firstquadlet and second quadlet of the packet data are stored in the IBOregister 59, and by examining the audio label 59-1 and audio sub-label59-2 in the IBO register 59, the system microcontroller 14 confirms thedata format of the packet data.

At time T13, RxLABEL CF50=0, RxLABEL CFD0=0, RxLABEL0=1, and RxLABELCF=0, so that received packet data is in the IEC 60958-conformat 94state. This state is the state in which packet data is judged in stepS13 to be in IEC 60958 format as a result of a “NO” branch in step S1 ofthe flowchart of the above-described FIG. 7.

As indicated by 97, the value of RxLABEL 0 changes from 0 (off) to 1(on), so that it is judged that a stream change from SACD to IEC60958-conformant format has ended.

FIG. 17 is a drawing showing an example of a stream change of packetdata from SACD format to DVD format.

In FIG. 17, prior to time T21, RxLABEL CF50=0, RxLABEL CDD0=0,RxLABEL0=0, and RxLABEL CF=0, so that the format of the received packetdata is the SACD 101 state. This state is the state in which packet datais judged in step S10 to be in 1-bit audio (SACD) format as a result ofa “YES” branch in step S9 of the flowchart of the above-described FIG.7.

At time T21, as indicated by 105, the value of RxLABEL CF50 has changedfrom 0 (off) to 1 (on), so that a stream change ending SACD 101 data isdetected.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet of the packet data is CF58-1 andmoreover that the leading byte of the second quadlet is CF58-2, and theCF detection means turns on RxLABEL CF57; the system microcontroller 14,by detecting the on state of RxLABEL CF57, detects the occurrence of astream change in the packet data.

Next, the CF50 detection means detects the face that the leading twobytes of the first quadlet of the packet data are CFD1 and that theleading two bytes of the second quadlet are CF50, and the CF50 detectionmeans turns on the CF50 flag 51; the system microcontroller 14, bydetecting the on state of the CF50 flag 51, detects a stream changeending the SACD data 52.

In the interval from time T21 to time T22, RxLABEL CF50=1, RxLABELCFD0=0, RxLABEL0=0, and RxLABEL CF=1, so that the received packet datais in the SACD ancillary no-data 102 state.

In the interval from time T22 to time T23, RxLABEL CF50=0, RxLABELCFD0=1, RxLABEL0=0, and RxLABEL CF=1, so that the received packet datais in the DVD ancillary no-data 103 state.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet of the packet data is CF58-1 andmoreover that the leading byte of the second quadlet is CF58-2, and theCF detection means turns on RxLABEL CF57; the system microcontroller 14,by detecting the on state of RxLABEL CF57, can detect the occurrence ofa stream change in the packet data.

Next, the CFD0 detection means detects that the two leading bytes of thefirst quadlet of the packet data are CFD0 and that the two leading bytesof the second quadlet are CFD0. At this time, the CFD0 detection meansturns on the CFD0 flag 53, and the system microcontroller 14, bydetecting the on state of the CFD0 flag 53, detects that a stream changehas occurred in the packet data to the DVD audio data format 54.

As indicated by 106, there is only one RxLABEL on state, for CFD0, sothat the packet data is judged to be in the DVD format with the RxLABELCFD0 in the on state. At this time, the received packet is confirmed,the data length is confirmed, and the IEEE 1394 microcontroller 13 shownin FIG. 1 sets the IEEE 1394 link chip 12 to the DVD 104 formatreception state.

At time T23, RxLABEL CF50=0, RxLABEL CFD0=1, RxLABEL0=0, and RxLABELCF=0, so that the received packet data is in the DVD 104 state. Thisstate is the state in which packet data is judged in step S5 to be inthe multi-bit audio (DVD audio) format as a result of a “YES” branch instep S4 of the flowchart of the above-described FIG. 7.

As indicated by 107, the value of RxLABEL CF has changed from 1 (on) to0 (off), so that it is judged that a stream change from SACD 101 to DVD104 has ended.

FIG. 18 is a drawing showing an example of a stream change of packetdata from SACD 5-channel format to SACD 6-channel format.

In FIG. 18, prior to time T31, RxLABEL CF50=0, RxLABEL CFD0=0,RxLABEL0=0, and RxLABEL CF=0, so that the format of received packet datais in the SACD 111 state. This state is the state in which packet datais judged in step S10 to be in 1-bit audio (SACD) format as a result ofa “YES” branch in step S9 of the flowchart of the above-described FIG.7.

At time T31, as indicated by 115, the value of RxLABEL CF50 changes from0 (off) to 1 (on), so that a stream change ending the SACD 111 data isdetected.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet of the packet data is CF58-1 andmoreover the leading byte of the second quadlet is CF58-2, and the CFdetection means turns on RxLABEL CF57, so that the systemmicrocontroller 14, by detecting the on state of RxLABEL CF57, candetect that a stream change in the packet data has occurred.

Next, the CF50 detection means detects that the leading two bytes of thefirst quadlet of the packet data are CFD1 and that the leading two bytesof the second quadlet are CF50, and the CF50 detection means turns onthe CF50 flag 51; the system microcontroller 14, by detecting the onstate of the CF50 flag 51, detects a stream change ending the SACD data52.

In the interval from time T31 to time T32, RxLABEL CF50=1, RxLABELCFD0=0, RxLABEL0=0, and RxLABEL CF=1, so that the received packet datais in the SACD ancillary no-data 112 state.

As indicated by 116, the only RxLABEL on state is CF50, and so theformat is set to the SACD format of this RxLABEL CF50 on state. At thistime, the received packet is confirmed, the data length is confirmed,and the IEEE 1394 microcontroller 13 shown in FIG. 1 sets the IEEE 1394link chip 12 to the SACD 111 format reception state.

During the interval from time T32 to time T33, RxLABEL CF50=1, RxLABELCFD0=0, RxLABEL0=0, and RxLABEL CF=1, so that received packet data is inthe SACD ancillary no-data 113 state.

At this time, as shown in FIG. 12, the CF detection means detects thatthe leading byte of the first quadlet of the packet data is CF58-1 andmoreover that the leading byte of the second quadlet is CF58-2, and theCF detection means turns on RxLABEL CF57; the system microcontroller 14,by detecting the on state of RxLABEL CF57, can detect that a streamchange has occurred in the packet data.

Next, the CF50 detection means detects that the leading two bytes of thefirst quadlet of the packet data are CFD1 and that the leading two bytesof the second quadlet are CF50, and the CF50 detection means turns onthe CF50 flag 51; the system microcontroller 14, by detecting the onstate of the CF50 flag 51, detects a stream change to SACD data 52.

Here, as indicated by 117, the IEEE 1394 microcontroller 13 repeats theoperation of setting the IEEE 1394 link chip 12 into the SACD formatreception state, but the data length changes, and so a change in thenumber of channels is detected.

At time T33, RxLABEL CF50=0, RxLABEL CFD0=0, RxLABEL0=0, and RxLABELCF=0, so that the received packet data is in the SACD state. This stateis the state in which packet data is judged in step S3 to be in the1-bit audio (SACD) format as a result of a “YES” branch in step S2 ofthe flowchart of the above-described FIG. 7.

As indicated by 118, the value of RxLABEL CF changes from 1 (on) to 0(off), so that a stream change from SACD 5-channel (111) format to SACD6-channel (114) format is judged to have ended.

FIG. 19 is a drawing showing a reception state when a receiver receivesstream data.

In FIG. 19, the IBO register 59 is a confirmation register 124, and theRxLABEL CF50 (51), RxLABEL CFD0 (53), RxLABEL0 (54), and RxLABEL CF (57)are in the trigger detection register 125.

Below, reception states 126 in each of the stream changes 121 to 123 areexplained.

In FIG. 19, a stream change in the packet data indicated by 121 (fromthe IEC 60958 format to the SACD format) is the reception state, in themultiformat-compatible receiver 11 shown in FIG. 1, for the case inwhich the packet data shown in the above-described FIG. 15 undergoes astream change from the IEC 60958 format to the SACD format.

In a stream change (from the IEC 60958 format to the SACD format) in thepacket data indicated by 121 in FIG. 19, during the interval from timeT1 to time T2, when the trigger detection register 125 detects thatRxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off, and RxLABEL0 (54)=off, asindicated by 126, the received packet is judged to be an empty packet,and the receiving side enters a mute state, in which audio is notoutput.

During the interval from time T2 to time T3, when the trigger detectionregister 125 detects that RxLABEL CF50 (51)=on, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by 126, priornotice is given that the received packet is in SACD format.

During the interval following time T3, when the trigger detectionregister 125 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=off, as indicated by 126, a stateis entered in which an SACD format reception packet is being received.

In FIG. 19, the packet data stream change indicated by 122 (from SACDformat to IEC 60958 format) is a reception state in themultiformat-compatible receiver 11, shown in FIG. 1, for the case of astream change in the packet data from SACD format to IEC 60958 format asshown in the above-described FIG. 16.

In a stream change (from SACD format to IEC 60958 format) in the packetdata indicated by 122 in FIG. 19, during the interval from time T1 totime T2, when the trigger detection register 125 detects that RxLABELCF50 (51)=on, RxLABEL CFD0 (53)=off, RxLABEL0 (54)=off, and RxLABEL CF(57)=on, as indicated by 126, the received packet is judged to be in astream change state, and the receiving side enters a mute state in whichaudio is not output.

During the interval from time T12 to time T13, when the triggerdetection register 125 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0(53)=off, and RxLABEL0 (54)=off, as indicated by 126, the receivedpacket is judged to be an empty packet, and the receiving side enters astate of preparation for reception of packet data in the IEC 60958format.

During the interval following time T13, when the trigger detectionregister 125 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=on, and RxLABEL CF (57)=off, as indicated by 126, an IEC60958 format reception packet is being received.

FIG. 20 is a drawing showing a reception state when a receiver receivesstream data.

In FIG. 20, the IBO register 59 is a confirmation register 134, and theRxLABEL CF50 (51), RxLABEL CFD0 (53), RxLABEL0 (54), and RxLABEL CF (57)are in the trigger detection register 135.

Below, reception states 136 in each of the stream changes 131 to 133 areexplained.

In FIG. 20, a stream change in the packet data indicated by 132 (fromthe SACD format to the DVD-audio format) is the reception state, in themultiformat-compatible receiver 11 shown in FIG. 1, for the case inwhich the packet data shown in the above-described FIG. 17 undergoes astream change from the SACD format to the DVD-audio format.

In a stream change (from the SACD format to the DVD-audio format) in thepacket data indicated by 132 in FIG. 20, during the interval prior totime T21, when the trigger detection register 135 detects that RxLABELCF50 (51)=off, RxLABEL CFD0 (53)=off, RxLABEL0 (54)=off, and RxLABEL CF(57)=off, as indicated by 136, an SACD format reception packet is beingreceived.

During the interval from time T21 to time T22, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=on, RxLABEL CFD0(53)=off, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by136, the received packet is judged to be in the SACD ancillary no-datastate, and on the receiving side a mute state is entered in which audiois not output.

During the interval from time T22 to time T23, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0(53)=on, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by 136,the received packet is judged to be a packet in DVD-audio format, andthe receiving side enters the mute state in which audio is not output.

During the interval following time T23, when the trigger detectionregister 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=off, a DVD-audio format receptionpacket is being received.

In FIG. 20, the stream change in the packet data indicated by 133(change in the number of SACD channels) is the reception state in themultiformat-compatible receiver 11 shown in FIG. 1 for the case of astream change in the packet data shown in the above-described FIG. 18from SACD 5-channel format to SACD 6-channel format.

In the stream change (change in the number of SACD channels) in thepacket data indicated by 133 in FIG. 20, during the interval prior totime T31, when the trigger detection register 135 detects that RxLABELCF50 (51)=off, RxLABEL CFD0 (53)=off, RxLABEL0 (54)=off, and RxLABEL CF(57)=off, as indicated by 136, an SACD 5-channel format reception packetis being received.

During the interval from time T31 to time T32, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=on, RxLABEL CFD0(53)=off, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by136, the received packet is judged to be in the SACD ancillary no-datastate, and the receiving side enters the mute state in which audio isnot output.

During the interval from time T32 to time T33, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=on, RxLABEL CFD0(53)=off, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by136, the received packet is in the SACD ancillary no-data state, but thereceiving side is in the mute state in which audio is not output, andthe received packet is judged to be in SACD 6-channel format.

During the interval following time T33, when the trigger detectionregister 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=off, as indicated by 136, an SACD6-channel format reception packet is being received.

In FIG. 19, a stream change (from IEC 60958 format to DVD-audio format)in the packet data indicated by 123 results in the reception state ofthe multiformat-compatible receiver 11 shown in FIG. 1 in the case of astream change in packet data from IEC 60958 format to DVD-audio format.

In a stream change (from IEC 60958 format to DVD-audio format) in packetdata indicated by 123 in FIG. 19, during the interval from time T01 totime T02, when the trigger detection register 135 detects that RxLABELCF50 (51)=off, RxLABEL CFD0 (53)=off, and RxLABEL0 (54)=off, asindicated by 136, the received packet is judged to be an empty packet,and the receiving side enters the mute state in which audio is notoutput.

During the interval from T02 to T03, when the trigger detection register135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=on, RxLABEL0(54)=off, and RxLABEL CF (57)=on, as indicated by 136, prior notice isgiven that the received packet is in DVD-audio format.

During the interval following time T03, when the trigger detectionregister 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=off, as indicated by 136, aDVD-audio format reception packet is being received.

Though not shown here, other stream changes (from IEC 60958 format toCD/MD format) result in similar states. The DVD-audio format is calledthe multibit linear audio (MBLA) format.

In FIG. 20, the stream change (from DVD-audio format to SACD format) inthe packet data indicated by 131 results in the reception state in themultiformat-compatible receiver 11 shown in FIG. 1 for the case of astream change in the packet data from DVD-audio format to SACD format.

In a stream change (from DVD-audio format to SACD format) in the packetdata indicated by 131 in FIG. 20, during the interval prior to timeT0111, when the trigger detection register 135 detects that RxLABEL CF50(51)=off, RxLABEL CFD0 (53)=off, RxLABEL0 (54)=off, and RxLABEL CF(57)=off, as indicated by 136, a DVD-audio format reception packet isbeing received.

During the interval from time T011 to time T012, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0(53)=on, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by 136,the received packet is judged to be in the DVD-audio ancillary no-datastate, and the receiving side enters the mute state in which audio isnot output.

During the interval from time T012 to time T013, when the triggerdetection register 135 detects that RxLABEL CF50 (51)=on, RxLABEL CFD0(53)=off, RxLABEL0 (54)=off, and RxLABEL CF (57)=on, as indicated by136, the received packet is judged to be in SACD format, and thereceiving side enters the mute state in which audio is not output.

During the interval following time T013, when the trigger detectionregister 135 detects that RxLABEL CF50 (51)=off, RxLABEL CFD0 (53)=off,RxLABEL0 (54)=off, and RxLABEL CF (57)=off, as indicated by 136, an SACDformat reception packet is being received.

As stated above, by means of operation of a microcontroller or otherjudgment means using the registers in the IEEE 1394 link chip 12 withinthe multiformat-compatible receiver 11 shown in FIG. 1 when receivingAM824 data, stream changes corresponding to data combinations can bedetected, and the subsequent data format can be judged.

When RxLABEL CF (57)=on, CF is contained in the audio label of the AM824data.

Then, when RxLABEL CF50 (51)=on, an SACD format packet is beingreceived. At this time, the audio label and sub-label of the secondquadlet of the AM824 data are CF50. Here the second quadlet is examinedbecause, in 1-bit audio and multi-bit audio, the positions of ancillarydata are different, so that if the second quadlet is checked it ispossible to discriminate the type of data content in the case of 1-bitaudio and the data format through the type of ancillary data in the caseof multi-bit audio. In this case, ancillary no-data for SACD or other1-bit audio data is included. That is, a stream change related to SACDor other 1-bit audio is occurring.

Next, when RxLABEL CFD0 (53)=on, a DVD-audio format packet is beingreceived. At this time, the audio label and sub-label of the secondquadlet of the AM824 data are CFD0. Here the second quadlet is examinedfor the same reason as the above-mentioned RxLABEL CF50 (51). In thiscase, ancillary no-data is included in the DVD-audio or other multi-bitlinear audio data. That is, a stream change related to the DVD-audio orother multibit linear audio is occurring.

Next, when RxLABEL0 (54)=on, a CD/MD format packet is being received. Atthis time, when the leading four bits of the AM824 data are 0, the databeing received is IEC 60958-conformant data.

The contents of the IBO register are the audio label and sub-label fortwo received quadlets. Here received data is normally stored. Byconfirming this audio label and sub-label, the format of the datacurrently being received can be confirmed.

Here, if data allocated to each register is detected, the format of thedata in the stream change can be judged and confirmed.

Further, in cases other than a stream change in the packet data, thatis, when AM824 data is constantly being input, the current AM824E formatcan be judged from the audio label and sub-label of the IBO register.

As explained above, when IEC 60958-conformant (CD/MD or similar) data isbeing received, and SACD or other 1-bit audio data is then received, thefollowing procedure is used to judge that the packet data is in SACDformat.

First, when IEC 60958-conformant data is being input constantly,PxLABEL0 (54)=on. Next, when a stream change occurs so that the packetdata changes to a different format, in order to indicate this change,the receiver receives ancillary no-data or empty packet data. At thistime, RxLABEL0 (54)=off, and the beginning of the stream change can bedetected. Here, as an example, when SACD 1-bit audio data is received,RxLABEL CF (57)=on results, indicating this SCAD anceillary no-data. Atthis time, if a state obtains in which only one RxLABEL is on, the dataformat can be confirmed to be SACD, so that the IEEE 1394microcontroller 13 within the multiformat-compatible receiver 11 shownin FIG. 1 can set the IEEE 1394 link chip 12 to the reception mode forthe SACD format. Finally, when a stream change ends, SACD format data isconstantly input, and RxLABEL CF50 (51)=off; further, RxLABEL CF(57)=off, and the end of the stream change can be judged.

Also, when SACD or other 1-bit audio data is being received, and IEC60958-conformant (CD/MD or similar) data is then received, when judgingthat the data is IEC 60958-conformant, the following procedure is used.

When a stream change occurs because SACD or other 1-bit audio data hadbeen input constantly and the data format of the packet data is changed,the receiver receives ancillary no-data, RxLABEL CF50 (51) is turned on,and the beginning of a stream change can be detected. Next, if as anexample IEC 60958-conformant data arrives, all the RxLABEL flags areturned off, and it can be predicted that a stream change is occurring toIEC 60958-conformant data. Because there exists equipment which, due topast standards, does not use IEC 60958-conformant ancillary no-data, ajudgment cannot be made solely on the basis of ancillary no-data.However, in this case it is certain that the packet data is not in a1-bit audio or multi-bit audio format, and so the IEC 60958-conformantformat is predicted, and by examining the audio label and sub-label ofactually received data, the format can be determined reliably, so thatthe IEEE 1394 microcontroller 13 within the multiformat-compatiblereceiver 11 shown in FIG. 1 can set the IEEE 1394 link chip 12 to theIEC 60958-conformat reception mode. Finally, when IEC 60958-conformantdata actually arrives, RxLABEL0 (54) is turned on, and the end of thestream change can be judged. In this case, ancillary no-data is notused, and so the end of the stream change cannot be judged from thestate of RxLABEL CF (57); but the stream change end can be judged fromthe above-described turning on of RxLABEL0 (54).

In cases where SACD or other 1-bit audio data is being received, andthen DVD-audio or other multi-bit linear audio data is received, thefollowing procedure is used to judge that the data is DVD-audio.

First, when 1-bit audio data is arriving, and then the format of thepacket data changes so that a stream change occurs, RxLABEL CF (57) isturned on. At this time, if only one RxLABEL is turned on, it can beconfirmed that the next data format is the multi-bit audio data format,and so the IEEE 1394 microcontroller 13 within themultiformat-compatible receiver 11 shown in FIG. 1 can set the IEEE 1394link chip 12 into the multi-bit audio reception mode. Finally, whenmulti-bit audio data arrives, RxLABEL CF50 (51) is turned off, andRxLABEL CF (57) is turned off, so that the stream change end can bejudged.

Next, when a stream change is detected when the data format does notchange but the number of channels of audio data changes, the followingprocedure is used. As an example, the case in which there is a change inSACD data, which is 1-bit audio data, from 5 channels to 6 channels isexplained.

When there are a plurality of channels, the data size changes dependingon the number of channels. This data size is stated as the data lengthin the 1394 header. It is sufficient to be able to judge differences inthis data length.

In this example, 1-bit audio data is received in a continuous state;when a stream change occurs in order to change the number of channels ofthe packet data, RxLABEL CF50 (51) is turned on. At this time, thebeginning of the stream change can be detected. When the stream changeis detected, the ancillary no-data data length is confirmed, and thenumber of channels is judged from the data size. RxLABEL CF50 (51)=oneven when the next ancillary no-data arrives, and so detection at theinstant of the change is not possible; but according to AM824Estandards, the interval for output of ancillary no-data is 10 msec orlonger, and so if this check is repeated at fixed intervals, a change inthe data length can be detected. By means of this detection, the numberof channels of new data can be judged, and the IEEE 1394 microcontroller13 within the multiformat-compatible receiver 11 shown in FIG. 1 can setthe IEEE 1394 link chip 12 to the reception mode for the detected numberof channels. Finally, when actual data arrives, all RxLABEL flags areturned off, and RxLABEL CF(57)=off, so that the end of the stream changecan be judged.

The Direct Stream Digital (DSD) method adopted by SACD is a method whichrepresents the magnitude of audio signals using the density(concentration) of 1-bit digital pulses, and is completely differentfrom the conventional Pulse Code Modulation (PCM) method.

In the above-described aspect, an example was described which uses anIEEE 1394-standard interface; however, the present invention is notthereby limited, and other interfaces such as a USB (Universal SerialBus) interface or wireless IEEE 1394-standard interface may be used.

The signal reproduction device of this invention comprises receptionmeans to receive transmitted transmission signals resulting from theconversion of data in a plurality of prescribed signal formats into aprescribed packet type; reproduction means to reproduce signals in aprescribed signal format from transmission signals received by thereception means and converted into packets; packet extraction means toextract a prescribed packet of transmission signals received by thereception means; modification data detection means to detect, in anextracted packet, data indicating that modification has been performedfrom the currently received prescribed signal format to anotherprescribed signal format; and, control means to send, to thereproduction means, parameters necessary for reproduction by thereproduction means, from signals received and converted into packets tosignals in another prescribed signal format, based on detected signalformat modification data. Hence there is the advantageous result thatthe data format can be automatically judged from the input data, anddata can be reproduced.

Further, a signal reproduction device of this invention furthercomprises output means to output signals reproduced by the reproductionmeans of the above-described signal reproduction device; when signaltype modification data is detected, the control means can suppress theoutput of signals from the output means during the period untilcompletion of the signal format conversion, so that there is theadvantageous result that degradation of the quality of reproducedsignals accompanying modification of the signal format can be prevented.

Also, a signal reproduction device of this invention has the furtheradvantageous result that, in the above description, data indicatingmodification of the signal format is such that, after transmission of asignal indicating that transmitted data in the signal format currentlybeing received is invalid data, data indicating the signal format of thedata to be transmitted next is transmitted, so that the next data formatcan be predicted and reception settings for this data can be set inadvance.

Also, a signal reproduction device of this invention has the furtheradvantageous result that, in the above description, the signalreproduction device detects other signal formats through the packet sizeof received data, so that when the data size changes due to a change inthe number of channels, because the data size is described as the datalength in the header, by judging differences in the data length it ispossible to judge changes in the number of channels.

Also, a signal reproduction method of this invention comprises areception step, in which transmission signals, obtained by convertingdata in a plurality of prescribed signal formats into a prescribedpacket format and transmitting, are received; a reproduction step, inwhich signals in a prescribed signal format are reproduced fromtransmission signals converted into packet form, received in thereception step; a packet extraction step, in which a prescribed packetof transmission signals received in the reception step is extracted; amodification data detection step, in which data is detected, in anextracted packet, indicating that modification has been performed fromthe currently received prescribed signal format to another prescribedsignal format; and, a control step, in which, based on the detectedsignal format modification data, parameters necessary for reproductionof signals in another prescribed signal format from received signalsconverted into packets in the reproduction step are sent to thereproduction step. Hence there is the advantageous result that the dataformat can be automatically judged from the input data, and reproductionprocessing can be performed.

INDUSTRIAL APPLICABILITY

This signal reproduction device examines received data packets andautomatically recognizes the data format, and through the operation of amicrocontroller or other judgment means utilizing the registers of anIEEE 1394 link chip within a multiformat-compatible receiver which hasreceived AM824 data, detects stream changes according to datacombinations and can judge the next data format. The signal reproductiondevice can be applied to, for example, IEC 60958-conformant format dataamong the formats conforming to the audio and music data transmissionprotocol 1.0 and AMDTR 2.0, to DSD (Digital Stream Direct) format data,and to DVD (Digital Versatile Disc) audio format data.

DESCRIPTION OF REFERENCE NUMERALS 1 MULTIFORMAT-COMPATIBLE TRANSMITTER 2DISC 3 DSP 4 IEEE 1394 LINK CHIP 5 IEEE MICROCONTROLLER 6 SYSTEMMICROCONTROLLER 7 OPERATION PORTION 8 DISPLAY PORTION 11MULTIFORMAT-COMPATIBLE RECEIVER 12 IEEE 1394 LINK CHIP 13 IEEEMICROCONTROLLER 14 SYSTEM MICROCONTROLLER 15 OPERATION PORTION 16DISPLAY PORTION 17 D/A CONVERTER 18 SPEAKER 19 CFR READING 20 RECEIVEDFORMAT SETTING 21 IEEE 1394 PACKET 22 1394 HEADER 23 AM824 FLAG 24 AM824DATA 25 DATA 26 REGISTER 27 CF50 FLAG 28 ANCILLARY NO-DATA 29 STREAMCHANGE DETECTION 41 IEC 60958-CONFORMANT 42 MULTI-BIT LINEAR AUDIO 43ONE-BIT AUDIO DATA 44 ANCILLARY NO-DATA IEC 60958-CONFORMANT FORMAT 45ANCILLARY NO-DATA MULTI-BIT LINEAR AUDIO 46 ANCILLARY NO-DATA ONE-BITAUDIO DATA 51 CF50 FLAG 52 SACD DATA 53 CFD0 FLAG 54 DVD AUDIO 55RxLABEL0 (ON) 56 CD/MD DATA (IEC 60958) 57 RxLABEL0 (ON) 58 AUDIO LABELCF 59 IBO REGISTER 60 DATA FORMAT CONFIRMATION 61 AM824E STREAM 62 IEC60958 CONTEXT 63 SACD CONTEXT 64 IEC 60958 DATA 65 IEC 60958 ANCILLARYNO-DATA 66 SACD ANCILLARY NO-DATA 67 SACD

1. A signal reproduction device, comprising: reception means to receivetransmission signals transmitted after conversion of data in a pluralityof prescribed signal formats into a prescribed packet type; reproductionmeans to reproduce signals in a prescribed signal format from saidtransmission signals received by said reception means and converted intopackets; packet extraction means to extract a prescribed packet fromsaid transmission signals received by said reception means, in order todetect a signal format of data transmitted by said transmission signalsreceived by said reception means; modification data detection means todetect, from said extracted packet, modification from said prescribedsignal format currently being received to another prescribed signalformat using a packet size of said extracted packet, and to generatesignal format modification data; and, control means to send, to saidreproduction means, parameters necessary for reproduction by saidreproduction means, from said transmission signals received by saidreception means and converted into packets to signals in said otherprescribed signal format, based on said detected and generated signalformat modification data.
 2. The signal reproduction device according toclaim 1, wherein said signal reproduction device further comprisesoutput means to output signals reproduced by said reproduction means,and wherein when said control means detects said signal formatmodification data, output of signals from said output means issuppressed during an interval until completion of said signal formatmodification.
 3. The signal reproduction device according to claim 1,wherein said signal format modification data is such that, after asignal is transmitted indicating that data transmitted in saidprescribed signal format currently being received is invalid data, dataindicating said other prescribed signal format of subsequentlytransmitted data is transmitted.
 4. The signal reproduction deviceaccording to claim 1, wherein data in said prescribed signal formatconforms to the IEEE 1394 standard.
 5. A signal reproduction method,comprising: a reception act, in which transmission signals, transmittedafter conversion of data in a plurality of prescribed signal formatsinto a prescribed packet format, are received; a reproduction act, inwhich signals in a prescribed signal format are reproduced from saidtransmission signals converted into said prescribed packet format,received in said reception act; a packet extraction act, in which aprescribed packet is extracted from said transmission signals receivedby said reception means, in order to detect a signal format of datatransmitted by said transmission signals; a modification data detectionact, in which, from said extracted packet, modification from saidprescribed signal format currently being received to another prescribedsignal format is detected using a packet size of said extracted packet,and signal format modification data is generated; and, a control act, inwhich, based on said detected and generated signal format modificationdata, parameters necessary for reproduction of signals in said otherprescribed signal format from said transmission signals converted intosaid prescribed packet format in said reproduction act are sent to saidreproduction act.
 6. The signal reproduction method according to claim5, further comprising an output act in which signals reproduced in saidreproduction act are output, and wherein, when said signal formatmodification data is detected in said control act, output of signals insaid output act is suppressed during an interval until completion ofsaid signal format modification.
 7. The signal reproduction methodaccording to claim 5, wherein said signal format modification data issuch that, after a signal is transmitted indicating that datatransmitted in said prescribed signal format currently being received isinvalid data, data indicating said other prescribed signal format ofsubsequently transmitted data is transmitted.
 8. The signal reproductionmethod according to claim 5, wherein data in said prescribed signalformat conforms to the IEEE 1394 standard.